Prior Art
Various methods are known for producing the compound represented by the formula [III]. These include the method starting from 4-methyl-5-chloromethyl-imidazole (Japanese Patent Laid-Open No. 142271/1981), the method starting from 4-methyl-5-mercaptomethylimidazole (Japanese Patent Publication No. 40547/1979, No. 56709/1985, No. 40667/1986), and the method starting from a halogenated diacetyl. Also disclosed are the methods using, as starting material, the compound represented by the formula [I], ##STR5## (Japanese Patent Publication No. 43832/1977, No. 1309/1981, No. 14460/1984).